I hope they come out alive, regardless of how much money they have (the latter seemingly being a problem for some people).
It’s all relative, them spending a quarter of a million dollars each could be the equivalent of us spending a couple of hundred quid.
I used to be quite a technical diver, and about 20 years ago I dived on trimix to 100 metres, and getting down is piece of cake, but surfacing took 4 hours including a change from trimix to oxygen. I paid about £500 for this experience (which included a shed load of additional training and gradually deeper dives), because I wanted to try the experience of going that deep on tanks. So to criticise people who have the wherewithal to try something that 99.99999% of us will never have the opportunity to experience is, I feel, a little unfair.
Some people like to push boundaries. If we didn’t, we’d never have landed on the moon.